Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next

Alexei Starovoitov says:

====================
pull-request: bpf-next 2019-05-31

The following pull-request contains BPF updates for your *net-next* tree.

Lots of exciting new features in the first PR of this developement cycle!
The main changes are:

1) misc verifier improvements, from Alexei.

2) bpftool can now convert btf to valid C, from Andrii.

3) verifier can insert explicit ZEXT insn when requested by 32-bit JITs.
   This feature greatly improves BPF speed on 32-bit architectures. From Jiong.

4) cgroups will now auto-detach bpf programs. This fixes issue of thousands
   bpf programs got stuck in dying cgroups. From Roman.

5) new bpf_send_signal() helper, from Yonghong.

6) cgroup inet skb programs can signal CN to the stack, from Lawrence.

7) miscellaneous cleanups, from many developers.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 22 insertions, 24 deletions

diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c
index 242a643af82f..33fb292f2e30 100644
--- a/kernel/bpf/core.c
+++ b/kernel/bpf/core.c
@@ -1795,38 +1795,33 @@ struct bpf_prog_array *bpf_prog_array_alloc(u32 prog_cnt, gfp_t flags)
 	return &empty_prog_array.hdr;
 }
 
-void bpf_prog_array_free(struct bpf_prog_array __rcu *progs)
+void bpf_prog_array_free(struct bpf_prog_array *progs)
 {
-	if (!progs ||
-	    progs == (struct bpf_prog_array __rcu *)&empty_prog_array.hdr)
+	if (!progs || progs == &empty_prog_array.hdr)
 		return;
 	kfree_rcu(progs, rcu);
 }
 
-int bpf_prog_array_length(struct bpf_prog_array __rcu *array)
+int bpf_prog_array_length(struct bpf_prog_array *array)
 {
 	struct bpf_prog_array_item *item;
 	u32 cnt = 0;
 
-	rcu_read_lock();
-	item = rcu_dereference(array)->items;
-	for (; item->prog; item++)
+	for (item = array->items; item->prog; item++)
 		if (item->prog != &dummy_bpf_prog.prog)
 			cnt++;
-	rcu_read_unlock();
 	return cnt;
 }
 
 
-static bool bpf_prog_array_copy_core(struct bpf_prog_array __rcu *array,
+static bool bpf_prog_array_copy_core(struct bpf_prog_array *array,
 				     u32 *prog_ids,
 				     u32 request_cnt)
 {
 	struct bpf_prog_array_item *item;
 	int i = 0;
 
-	item = rcu_dereference_check(array, 1)->items;
-	for (; item->prog; item++) {
+	for (item = array->items; item->prog; item++) {
 		if (item->prog == &dummy_bpf_prog.prog)
 			continue;
 		prog_ids[i] = item->prog->aux->id;
@@ -1839,7 +1834,7 @@ static bool bpf_prog_array_copy_core(struct bpf_prog_array __rcu *array,
 	return !!(item->prog);
 }
 
-int bpf_prog_array_copy_to_user(struct bpf_prog_array __rcu *array,
+int bpf_prog_array_copy_to_user(struct bpf_prog_array *array,
 				__u32 __user *prog_ids, u32 cnt)
 {
 	unsigned long err = 0;
@@ -1850,18 +1845,12 @@ int bpf_prog_array_copy_to_user(struct bpf_prog_array __rcu *array,
 	 * cnt = bpf_prog_array_length();
 	 * if (cnt > 0)
 	 *     bpf_prog_array_copy_to_user(..., cnt);
-	 * so below kcalloc doesn't need extra cnt > 0 check, but
-	 * bpf_prog_array_length() releases rcu lock and
-	 * prog array could have been swapped with empty or larger array,
-	 * so always copy 'cnt' prog_ids to the user.
-	 * In a rare race the user will see zero prog_ids
+	 * so below kcalloc doesn't need extra cnt > 0 check.
 	 */
 	ids = kcalloc(cnt, sizeof(u32), GFP_USER | __GFP_NOWARN);
 	if (!ids)
 		return -ENOMEM;
-	rcu_read_lock();
 	nospc = bpf_prog_array_copy_core(array, ids, cnt);
-	rcu_read_unlock();
 	err = copy_to_user(prog_ids, ids, cnt * sizeof(u32));
 	kfree(ids);
 	if (err)
@@ -1871,19 +1860,19 @@ int bpf_prog_array_copy_to_user(struct bpf_prog_array __rcu *array,
 	return 0;
 }
 
-void bpf_prog_array_delete_safe(struct bpf_prog_array __rcu *array,
+void bpf_prog_array_delete_safe(struct bpf_prog_array *array,
 				struct bpf_prog *old_prog)
 {
-	struct bpf_prog_array_item *item = array->items;
+	struct bpf_prog_array_item *item;
 
-	for (; item->prog; item++)
+	for (item = array->items; item->prog; item++)
 		if (item->prog == old_prog) {
 			WRITE_ONCE(item->prog, &dummy_bpf_prog.prog);
 			break;
 		}
 }
 
-int bpf_prog_array_copy(struct bpf_prog_array __rcu *old_array,
+int bpf_prog_array_copy(struct bpf_prog_array *old_array,
 			struct bpf_prog *exclude_prog,
 			struct bpf_prog *include_prog,
 			struct bpf_prog_array **new_array)
@@ -1947,7 +1936,7 @@ int bpf_prog_array_copy(struct bpf_prog_array __rcu *old_array,
 	return 0;
 }
 
-int bpf_prog_array_copy_info(struct bpf_prog_array __rcu *array,
+int bpf_prog_array_copy_info(struct bpf_prog_array *array,
 			     u32 *prog_ids, u32 request_cnt,
 			     u32 *prog_cnt)
 {
@@ -2090,6 +2079,15 @@ bool __weak bpf_helper_changes_pkt_data(void *func)
 	return false;
 }
 
+/* Return TRUE if the JIT backend wants verifier to enable sub-register usage
+ * analysis code and wants explicit zero extension inserted by verifier.
+ * Otherwise, return FALSE.
+ */
+bool __weak bpf_jit_needs_zext(void)
+{
+	return false;
+}
+
 /* To execute LD_ABS/LD_IND instructions __bpf_prog_run() may call
  * skb_copy_bits(), so provide a weak definition of it for NET-less config.
  */